Granted Patent
Utility
US 4,376,331 · App. 06/205,352
Valve spring compressor
Inventor:
James T. Clark
Patented Case
View Patent ↗
Granted: Mar 15, 1983
Filed: Nov 10, 1980
Inventor
James T. Clark
Assignee (at issue)
Parker-Hannifin Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.